1. Field of the Invention
The invention relates to a sizing agent-free tangled multifilament yarn.
2. Description of Related Art
Tangled multifilament yarns are sufficiently familiar. They are generally manufactured by means of blowing with a fluid, preferably air. The disadvantage of normal tangled multifilament yarns is that they lend themselves only conditionally to subsequent processing. For example, if tangled multifilament yarns are employed as warp yarns in weaving, they are subject to a large number of stresses, as portrayed in detail in the introduction to DE-A-43 27 371. In order to limit these stresses such that as few disruptions as possible arise during weaving, this specification recommends the use of stabilized sizing agent-free multifilament yarns. All multifilament yarns are considered to be stabilized which, under the warp thread tensions occurring as a result of the stresses on the loom and even in the plain weave L1/1, which is classified as particularly critical, can be worked with practically no disruptions with high end spacing, e.g., with an end spacing of 40/26 threads per cm warp/weft, not only on traditional loom systems, but most especially on modern loom systems based on weft insertion via air or water. According to DE-A-43 27 371, all yarns which only possess protective twist and which are rubbed, heat-sealed, glued, melted together or, more especially, intermingled, are suitable for use as stabilized multifilament yarns. In order to weave the yarns described therein, care must be taken that the thread tension of the multifilament yarn does not exceed 1 cN/dtex throughout the processing and until it passes through the weaving reed. Thus, in DE-A-43 27 371, no mention is made of a special method by which a multifilament can be especially well stabilized, but instead it is pointed out that evidently the usual yarns can be used, as long as the thread tension of the yarns is selected low enough during subsequent processing. However, since the thread tensions in looms, especially in looms based on weft insertion via air or water, are predetermined by the construction of the machine and can only be influenced to a small degree, the method suggested therein seems hardly to be practicable.
Another well-known method of making multifilament yarns suitable for weaving consists of providing the multifilament yarns with sizing agents in a separate step prior to weaving, which must, however, be washed out of the finished fabric again after weaving. JP-A-52 63 334 makes known, for example, the method of initially tangling the multifilament yarns in order to obtain an opening length of 2 to 5 cm (20 to 50 knots per meter), after which they are provided with sizing agent amounting to 0.5 to 3%. As a separate process step is necessary for applying the sizing agent, i.e., sizing cannot be combined with the process steps required for manufacturing and subsequent processing, sized yarns are very expensive to manufacture. As already explained, an additional step, namely, removal of the sizing agent, is also required after weaving. In addition, in a further expensive step, the sizing agent must then be removed from the washing water in order to protect the environment.
Furthermore, JP-A-41 63 336 makes known the method of adding waxes such as carnauba wax, beeswax or candelilla wax to the sizing agent which is applied to the tangled multifilament yarns. By mixing sizing agent with wax, however, processing the washing water with which the sizing agent is washed out of the finished fabric, becomes even more expensive.